英语句型分类：五大基本句型(5)

　　14. You must throw the broken pottery away at once. → The broken pottery must be thrown away at once.

　　15. Every one should give back his or her library books on time. → Library books should be returned on time.

　　16. People make great use of computers widely in the world. → Computers are widely used in the world.

　　【解析】

　　①主动句变被动句的方法是：首先把主动句的宾语变为被动句的主语，再把谓语动词变为被动语态，最后加上介词by的宾语(有时可省略)；

　　②被动句变为主动句的方法是：先把被动句中by的宾语变为主动句的主语(如被动句中省略了介词by及其宾语，一般可以用 we, you, they等作主语)，再把谓语动词改为主动语态(即把be去掉)，最后把被动句的主语改为主动句的宾语，主动句的时态与被动句中be的时态一致；

　　③在let, make, hear, see, watch等后的动词不定式在主动语态中不带to，变为被动语态时，要加上to；

　　④双宾语动词结构变为被动语态，则应在间接宾语前加上相应的介词to或for。如：

　　Li Lei was given a bike by Mr Wang. → Mr Wang gave a bike to Li Lei.

　　III. 二合并一成简单句

　　有时为了使句子结构更加紧凑，语言更加生动，我们可以把两个或两个以上的简单句合并为简单句，这样，句子意思上的联系显得更密切。

　　17. Lucy can't sing the English song "Yesterday Once More". And Lily can't sing it, either. → Neither Lucy nor Lily can sing the English song "Yesterday Once More".

　　18. This store sells men's shoes, and it also sells men's clothes. → This store sells not only men's shoes but also men's clothes.